Communication systems, whether wireless or wireline, are susceptible to interference, whether in the form of external noise or interfering signals from various stations of the communication systems themselves. Many schemes and protocols have been implemented to facilitate communications despite interference.
One protocol which has been widely implemented with respect to networks, such as local area networks (LANs) and metropolitan area networks (MANs), carrier sense multiple access (CSMA). In CSMA, stations (user stations, access points, routers, servers, etcetera) monitor the communication media to detect when the media is busy. If the media is determined to be busy, a station will not transmit. Once the media is determined to be free, a station may then utilize the media to transmit. Accordingly, CSMA provides an environment in which stations attempt to avoid interference, whether from sources external to the network or internal to the network, by monitoring the communication media and transmitting only when the communication media appears to be free.
Wireless communication networks are becoming ubiquitous. For example cellular telephone and data networks are becoming widely utilized. Wireless data networks, in particular, have seen dramatic growth in the availability and use. Accordingly, various infrastructure has been and is being developed to provide wireless data network coverage not only in the more traditional areas, such as within a home or office, but in large areas, such as throughout a metropolitan area. Wireless technologies, such as IEEE 802.11 (often referred to as “WiFi”), which were initially developed for use in servicing relatively small areas (e.g., homes and office buildings) have been deployed to provide wireless communications in much larger areas (e.g., large portions (e.g., 5 km radius) of an urban area.
Wireless networks are often desirable in that relatively little infrastructure (e.g., a basestation and backhaul trunk) may be deployed in order to serve a large service area. However, it is typically advantageous to accommodate a large number of stations through such infrastructure in order to provide a cost effective business model. For example, it is often desirable to serve as large of an area as is practicable using a single basestation in order to optimize the ratio of infrastructure costs to user revenue.
Unfortunately, not all infrastructure and their attendant protocols are particularly well suited to meet the demands of such large service area and/or high capacity deployments. For example, WiFi communication infrastructure utilizes CSMA which can result in undesired operation where a large area is served and/or a large number of stations are served. Such large service areas and/or large numbers of stations can result in the communication media utilized by a large number of stations being busy a substantial portion of the time, leaving little free time for stations to transmit. In particular, not only will a large number of stations being served in a large service area result in all stations in that service area being prevented from transmitting when any one station is transmitting, but in increasing the sensitivity of the radios in order to provide communications over the large area the radios become more susceptible to external interference. Accordingly, appreciable amounts of time may be experienced in which all stations in the service area are prevented from transmitting using CSMA due to external interference being detected on the communication media.